A biologically active substance uniformly dispersed microsphere and a sustained release formulation comprising the same

Abstract

The present application provides a microsphere comprising a lactic acid-glycolic acid copolymer (PLGA) as a main component, in which a biologically active substance is uniformly dispersed, wherein an average volume-based particle diameter of the microsphere is 1 μm or more and 150 μm or less, and a mass of the biologically active substance or an empty hole of 1.5 μm or more is not present in the microsphere. The microsphere of the present invention can appropriately control the initial release amount of the biologically active substance and its release rate during a subsequent release period, and can continuously release the biologically active substance in vivo for a predetermined period of time.

1 . A microsphere comprising a lactic acid-glycolic acid copolymer (PLGA) as a main component,
 wherein an average volume-based particle diameter of the microsphere is 1 μm or more and 150 μm or less,   a biologically active substance is uniformly dispersed inside the microsphere, and   a mass of the biologically active substance or an empty hole of 1.5 μm or more is not observed inside the microsphere, in an electron microscope image of a cross section of the microsphere.   
     
     
         2 . The microsphere according to  claim 1 , wherein a mass of the biologically active substance or an empty hole of 1.0 μm or more is not observed inside the microsphere. 
     
     
         3 . The microsphere according to  claim 1 , wherein an average volume-based particle diameter of the dispersed biologically active substance is 5 nm to 500 nm. 
     
     
         4 . The microsphere according to  claim 1 , wherein the biologically active substance is a lipophilic biologically active substance. 
     
     
         5 . A sustained release formulation comprising the microsphere according to  claim 1 . 
     
     
         6 . A sustained release formulation comprising the microsphere according to  claim 2 . 
     
     
         7 . A sustained release formulation comprising the microsphere according to  claim 3 . 
     
     
         8 . A sustained release formulation comprising the microsphere according to  claim 4 .